Weintraub told CNN that Persico died at Duke University Medical Center, not far from the federal prison in Butner, North Carolina, where he was serving his 139-year sentence. Weintraub said his client had just finished serving 36 years.

"From my legal relationship with Carmine, he was a great client, a nice guy, and a wonderful man," Weintraub told CNN affiliate WABC-TV.

Persico was responsible for running much of the organized crime in the United States as the longtime reputed boss of the Colombo crime family in New York City, WABC reported. He was convicted of racketeering and murder in the late 1980s, which WABC said was considered one of Rudy Giuliani's most triumphant victories against the mob when Giuliani was the US attorney in Manhattan. Persico reportedly ordered a hit on Giuliani in response, WABC said.

Persico acted as his own lawyer, drawing the praise of the judge and attorneys alike, according to a 1986 New York Times story.

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''You are a tragedy," Judge John F. Keenan told Persico during his sentencing in 1986, the Times reported. ''You are one of the most intelligent people I have seen in my life.''

Persico was born in 1933, according to the FBI's website. He grew up in Italian and Irish-American neighborhoods in Brooklyn, The New York Times reported. He got involved in gang activity as a teenager and quickly rose in the ranks to become the head of the Colombo family.

Persico earned the nickname "Snake" because he tried to strangle and kill a friend and fellow hitman in the early 1960s, the Times reported. But Persico didn't like it, preferring his other nickname, "Junior."